US President Barack Obama’s Asia pacific tour is winding down but the issues being discussed with his South Korean counterpart show no signs of a swift conclusion.Top of the agenda is what to do about the reclusive North’s atomic ambitions. Obama and President Lee Myung-bak are prodding Pyongyang to return to stalled nuclear talks. Speaking in Seoul, Obama said Washington would not be distracted by side issues thrown up by North Korea. ‘‘President Lee and I both agree on the need to break the pattern that has existed in the past. In which North Korea behaves in a provocative fashion, it then is willing to return to talks, it talks for a while, and then, leaves the talks seeking further concessions,’‘ Obama said. Earlier, protesters hit the streets of the South Korean capital urging Obama to get tough with Kim jung-il’s regime. In addition to North Korea, the thorny issue of a free trade agreement between Washington and Seoul is expected to top talks.